My new PM button has been flashing for months....and when i do get a new PM my email notificaton doesn't work half the time, so i guess it balances out. Sorta.
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .